The present invention relates to a pattern discriminating apparatus and, more particularly, to a pattern discriminating apparatus with improved discriminating precision.
A paper currency discriminating apparatus is known as a pattern discriminating apparatus of this type. FIG. 1 is a block diagram schematically showing the configuration of a conventional paper currency discriminating apparatus. Referring to FIG. 1, a detecting section 10 magnetically and optically detects the characteristics of a bill to be discriminated by such characteristics as magnetism, color, and intensity, and converts the detection results to an electric signal. An integrator 12 integrates the output signal from the detecting section 10 for all over the bill to be discriminated. An upper limit setting section 14 sets the upper limit of the output of the integrator 12 for a fit bill. A lower limit setting section 16 sets the lower limit of the output of the integrator 12 for the fit bill. A comparator 18 compares the output from the integrator 12 with the output from the upper limit setting section 14. A comparator 20 compares the output from the integrator 12 with the output from the lower limit setting section 16. A discriminating section 22 discriminates the authenticity, denomination, top or bottom surface and so on based on the comparison results from the comparators 18 and 20. The upper and lower limit setting sections 14 and 16 and the comparators 18 and 20 are incorporated in numbers corresponding to the number of different denomination of bills to be handled.
However, with a conventional paper currency discriminating apparatus of this type, as may be seen from FIG. 1, discriminations are made on authenticity, denomination, top or bottom surface and so on based only on the integrated value corresponding to all over the bill to be discriminated. Therefore, the paper currency discriminating apparatus of this type cannot discriminate between two groups of paper currency of different denominations for which the detection signals for magnetic strength or the like are different but for which the integrated value of these detection signals for each group of paper currency is the same. Furthermore, the paper currency discriminating apparatus of this type is also defective in that it cannot perform correct discrimination if there are variations in the pattern intensity of the bills or variations in the sensitivity of the detecting section.